#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize("O3")


#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[9]={1,0,-1,0,1,1,-1,-1,0};
const ll dx[9]={0,1,0,-1,1,-1,1,-1,0};
template <typename T> inline bool chmax(T &a, T b) {
  return ((a < b) ? (a = b, true) : (false));
}
template <typename T> inline bool chmin(T &a, T b) {
  return ((a > b) ? (a = b, true) : (false));
}

int main(){
  ll n,a,b;cin >> n >> a >> b;
  string s;cin >> s;
  vl v;
  ll cnt=0;
  s+="$$$$$$$$$$$$$$$$$$$$$";
  rep(i,n+10){
    if(s.substr(i,3)=="con"){
      cnt++;i+=2;
    }
    else{
      if(cnt)v.emplace_back(cnt);cnt=0;
    }
  }
  vl dp(n,-INF);//aをi回操作したときにbは何回操作できるか？
  dp[0]=0;
  for(auto p:v){
    per(i,n){
      if(dp[i]==-INF)continue;
      per(j,(p/a)+1){
        ll f=(p-a*j)/b;
        if(i+j<n){
          chmax(dp[i+j],dp[i]+f);
        }
      }
    }
    //rep(i,10)cout << dp[i] <<" ";cout << endl;
  }
  //rep(i,10)cout << dp[i] <<" ";cout << endl;
  ll ans=0;
  per(i,n){
    if(i>dp[i])chmax(ans,dp[i]*2+1);
    else chmax(ans,min(i,dp[i])*2);
  }
  cout << ans << endl;
}